1. Field of the Invention
The present invention relates generally to a method and apparatus for folding an airbag prior to disposing the airbag in an airbag apparatus to be installed in a steering wheel or the like of a vehicle. More particularly, the airbag is folded a plurality of times to predetermined widths in the lateral and longitudinal directions.
2. Description of the Related Art
A conventional method of folding airbags will be explained with reference to FIGS. 12 to 14. In one known folding method, a plurality of lateral folding bars 1 and longitudinal folding bars 2 are provided. Each folding bar has guide holes in its opposing ends. To accomplish folding, the appropriate number of lateral folding bar holding pin pairs 5,5 and longitudinal folding bar holding pin pairs 6,6 are set in the longitudinal and lateral directions on the working table 4. The pins support the folding bars 1 and 2 respectively during the lateral and longitudinal foldings. Usually, folding the airbag is carried out by two persons, including a main worker M1 who folds the airbag Z and a helper M2 who sets the folding bars and removes the folding bars after folding is completed.
To prepare for folding, the airbag Z is extended on the working table 4 and the air in the airbag 4 is exhausted through an inflater fitting hole (not illustrated) provided in the lower part of airbag Z. The helper M2 then sets the first folding bar 1a on the airbag Z and worker M1 makes the first outward fold F1 in a first side of airbag Z while pulling the airbag as shown in FIG. 12. Thereafter, the second folding bar 1b is set over the airbag and the first folding bar 1a. The airbag is then folded inward to create the first inward fold v1 in the first side of the airbag Z. In succession, the third folding bar is set over the second folding bar to make the second outward fold F2. After all of the lateral folds for one side of the airbag have been completed by repetition of such foldings, the opposing side of the airbag Z is folded by sequentially setting the folding bars in the same manner as previously described. Once the lateral folds have been completed, the worker M1 holds the airbag Z as the helper M2 removes the lateral folding bars 1, thereby completing the lateral folding. (FIG. 13).
The longitudinal folding is then done is the same way by changing the folding direction 90 degrees. More particularly, the longitudinal folding bar 2 is then set across the airbag Z (which has previously been laterally folded). The first longitudinal outward and inward folds L1, I1 and the second longitudinal outward fold L2 are carried out for the respective sides. Thereafter, the folding bars are removed, thus completing the longitudinal folding. (FIG. 14).
In the prior art method explained above, the size of the folding bar for the various folds are slightly different. Therefore, erroneous folds are sometimes been made because the helper's improperly sets the folding bars. Moreover, two persons are required for folding and thus, the man-hours required for folding are relatively high.